The present invention relates to a method for electrically connecting two sets of electrode terminals in array on the respective electronic board units such as a combination of a liquid crystal display panel, which may be referred to as a LCD panel hereinafter, and circuit board for driving the LCD panel. More particularly, the invention relates to a method for electrically connecting two sets of electrode terminals on the respective electronic board units such as a combination of two circuit boards and a combination of a LCD panel and a circuit board for driving the LCD panel by using a press-contact connector interposed therebetween.
Although the following description is given mainly for the combination of a LCD panel and a circuit board therefor, it may be too much to say that the scope of the present invention can be extended to any combinations of two electronic board units each bearing an array of electrode terminals.
It is a widely practiced prior art method for electrically connecting two sets of electrode terminals in array on the respective electronic board units such as a LCD panel and a heat-adhesive circuit board therefor that an anisotropic conductive film (ACF) is used for adhesively bonding a flexible printed circuit (FPC) board to the arrays of electrode terminals on the LCD panel and the circuit board under heating and pressing.
In the above mentioned method by hot-pressing with interposition of an ACF, however, it is indispensable to conduct an exact position matching work between the electrode terminals of the LCD panel and the electrode terminals of the circuit board so that the productivity of the assemblage process involving the above mentioned positioning work cannot be high enough.
Besides the above mentioned disadvantage of low productivity, the above mentioned electrical connecting method by hot-press bonding has a problem that the LCD panel is sometimes damaged by the pressure under heating. When the LCD panel is of the chip-on-glass (COG) type, in particular, the residual stress due to hot-press bonding causes a load on the LCD panel per se or the LCD panel-driving ICs resulting in softening of the ACF connecting the IC by the heat of hot-press bonding to cause failure of electrical connection of the IC for LCD panel driving.
The above mentioned troubles due to the heat in hot-press bonding can of course be alleviated by decreasing the temperature of hot-press bonding but at the sacrifice of the adhesive bonding strength of the ACF and reliability of electrical connection therewith.
Another serious problem in the above mentioned method for electrical connection is that, once a LCD panel and a circuit board have been connected together by hot-pressing of an ACF, the assemblage can hardly be disassembled into the respective parts without damaging the parts more or less even in need for testing or inspection desirably followed by repairing. Accordingly, it is the usual way that, when disorder is found in the assemblage, the most expensive LCD panel must be discarded even when the performance disorder is not due to the LCD panel per se.